A physical vapor deposition (PVD) chamber may include a chamber lid that is removable from the chamber body, for example, for chamber cleaning, maintenance or the like. The chamber lid may include non-vacuum regions, such as regions between a target assembly and grounding assembly of the chamber lid, or regions that hold a magnetron assembly, such as a cavity formed in the target assembly. The inventors have discovered that if a sufficient seal between non-vacuum regions of the chamber lid and regions of the chamber lid, such as the source material of the target are not established, then a sufficient vacuum seal between the chamber lid and the chamber body cannot be realized. A poor vacuum in the process chamber may result in diminished processing of substrates in the chamber. Further, poor contact between adjacent surfaces of the chamber lid and the chamber body due to weak vacuum forces can result in arcing between these surfaces.
Accordingly, the present invention provides substrate processing apparatus that may provide an improved capability for forming a vacuum in a process chamber.